1. Field of the Invention
The present invention relates to a heat- and oil-resistant electric insulated wire for use in a drawing line for automobiles, machine tools, generators, motors, etc., which is formed through the coating of a conductor with a specific insulating layer and in particular, to such an insulated wire wherein a separator such as a paper tape, polyester tape or the like is not required between a conductor and an insulating layer to provide a good producing workability and serviceability.
2. Description of the Prior Art
There are conventionally known heat- and oil resistant electic insulated wires made of a conductor coated with an insulating layer of vinylidene fluoride-based fluororubber. These insulated wires are being utilized in a drawing line for automobiles, machine tools, generators, motors, etc., due to heat and oil resistances of the insulating layer of vinylidene fluoride-based fluororubber.
With such conventional electric wires of vinylidene fluoride-based fluororubber, however, various disadvantages are encountered: During cross-linking, the insulating layer is adhered to the conductor, resulting in a degraded stripping property of a terminal insulator of the resultant wire. Therefore, in stripping the insulating layer on the terminal of the wire to place the wire into service, a long time is required for the stripping, leading to a difficulty of use. In addition, even after the insulating layer has been peeled off, some of the rubber remains on the conductor and for this reason, a solder would not be deposited onto such portion, or a conductive failure may be produced upon working of the terminal.
Thereupon, to overcome the above disadvantages, there has been proposed an electric wire having a separator, such as a paper tape or a polyester tape, interposed between a conductor and an insulating layer of a vinylidene fluoride-based fluororubber. With such wire, however, the separator is difficult to cut and a portion thereof may remain without being cut, in stripping the insulating layer at the terminal. Therefore, when the wire is to be placed into service, a long time is required and consequently, this wire is also difficult to use. Another disadvantage of this wire is that an operation of winding the separator around the conductor is required to provide an increase in production steps, resulting in an inferior production workability.